Par is a filter which copies its input to its output, changing all
white characters (except newlines) to spaces, and reformatting
each paragraph.  Paragraphs are separated by protected, blank, and
bodiless lines, and optionally delimited by indentation.

Each output paragraph is generated from the corresponding input
paragraph as follows:

1) An optional prefix and/or suffix is removed from each input line.
2) The remainder is divided into words (separated by spaces).
3) The words are joined into lines to make an eye-pleasing paragraph.
4) The prefixes and suffixes are reattached.

If there are suffixes, spaces are inserted before them so that they
all end in the same column.
